I would not put your small goldfish in with the others unless you are planning on using it as a food fish???
If you want to keep it alive then buy a preform pool, or a kiddie pool, or even a plastic Sterilite bin that you can plant into the ground and fill with water-the ground will support the walls of the bin as the water would push the walls outward.

Thanks terrestrial. I'm not sure how the makeshift pond would take to a cold winter. my goal is to let him swim with his family and friends. must be lonely in that small tank in the house. maybe I'll buy a larger tank and keep him inside till next year when he's larger. He spent his first winter in a weighted killie pot at the bottom of the pond. come summer I moved him into an inverted cat carrying case in the shallows where I fed him separately. This kept him safe from the predators but the bass had his nose against that cage constantly. I thought I would buy a same sized goldfish to see if the others would eat him. But that's like killing your neighbors kid. too emotionally invested??? So the goldfishes sentence will be another year in isolation or a possible death sentence. I'll call his lawyer. LOL

Yay! A ready-made excuse to build yet another pond, this time just for goldfish, lol.

Well, now you know why channel catfish and bass aren't great for ornamental ponds....:)

New pond for goldfish is in order....

Thanks for your input. We re-did the pond making it larger deeper bigger and better two years ago 2500gal. During the reconstruction I lost all but one of the smallmouth bass and 1 catfish survived as well. Losing those friends still brings me to tears. The Koi and goldfish were rescues. Their doing fine together. Maybe I'll give away their goldfish baby. My husbands about the "ornamental". Me? It's the occupants :~~~(